A stereo display technique is known which makes a viewer recognize a stereo image by displaying images with a disparity to watch them with the left and right eyes, respectively. The image watched with the left eye is deviated a little from the image watched with the right eye in manner of triangulation. The viewer judges whether the object is frontward or backward by grasping the deviation in manner of triangulation. In other words, a three-dimensional image with a binocular disparity between images is necessary to realize a stereo display.
In recent years, a technique is developed which generates such an image to make it possible to display, in a three-dimension, a two-dimensional image including no three-dimensional information originally as a conventional television broadcast. When the three-dimensional image is created from the two-dimensional image, the disparity indicating how much the image watched with the left eye is deviated from the image watched with the right eye is very important. When an object is imaged with a single camera, the information of depth is lost. Therefore, it is a problem in converting the two-dimensional image to the three-dimensional image how the depth is obtained. For example, JP-A 7-264631 (KOKAI) provides a method for realizing a stereoscopic view by detecting a motion vector from a reference frame of a two-dimensional image to another frame, determining a frame delay amount based on a horizontal component of the motion vector, determining an amount of delay of a frame and a line based on a vertical component of the motion vector, creating a disparity image corresponding to the reference frame from the amount of delay of the frame and line, and converting this disparity image into a stereoscopic image based on a motion stereo principle. However, this method can create a correct disparity image by compensating up-and-down motion of the whole screen, but cannot create a correct disparity image because an object is wobbled when the object moves locally in the screen.
In addition, JP-A 2000-261828 (KOKAI) provides a method for detecting a motion vector and a background region, calculating a background vector from the motion vector of the background region, calculating a relative vector by reducing the background vector from all motion vectors, and creating such a disparity image that the object draws closer the viewer as the relative vector increases. However, this method may provide an unreasonable disparity image such that the object existing in the back is located on the front.